Providing Video-on-Demand Services for Popular Videos
Lixin Gao, Smith College October 24th, 1998

We provide a formal framework for studying broadcasting schemes and design a family of schemes for broadcasting popular videos, called the {\it Greedy Disk-conserving Broadcasting} (GDB) scheme. We analyze the resource requirements for GDB, i.e., the number of server broadcast channels, the client storage space, and the client I/O bandwidth required by GDB. The analysis shows that GDB exhibits a tradeoff between any two of the three resources. We compare our scheme with a recently proposed broadcasting scheme, {\it Skyscraper Broadcasting} (SB). With GDB, we can reduce the client storage space by as much as 50\% or the number of server channels by as much as 30\% at the cost of a small additional increase in the amount of client I/O bandwidth. If we require the client I/O bandwidth of GDB to be identical to that of SB, GDB needs only 70\% of the client storage space required by SB or one less server channel than SB does. In addition, we show that with small client I/O bandwidth, the resource requirements of GDB are close to the minimum achievable by {\it any} disk-conserving broadcasting scheme.